JP2010251501A - Cryostat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cryostat having a structure which can be manufactured relatively easily, even if it has a complex shape. <P>SOLUTION: In a cryostat, at least a part of an outer vessel which is formed to include an inner vessel filled with a cryogenic refrigerant is formed of a cylindrical body. In the cryostat, split pieces of the cylindrical body which is split at least into two along an axial direction are reconfigured as cylindrical bodies. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cryostat, and more particularly, to a structure that allows easy installation of a thermal shield.

  As one type of nondestructive biopsy system, there is a SQUID (Superconducting Quantum Interference Device) magnetic flux measurement system that measures biomagnetism such as brain using the Josephson effect at cryogenic temperatures.

  In such a SQUID magnetic flux measurement system, a cryostat as shown in FIG. 4 has been conventionally used to cool and hold a measurement sensor and the like.

  In FIG. 4, the main body of the cryostat 1 is formed by an inner tank 2 and an outer tank 3, and in order to measure extremely weak magnetic signals in a biomagnetic measuring device represented by a magnetoencephalograph, they are made of, for example, glass fiber. It is made of reinforced plastic (Glass Fiber Reinforced Plastics, hereinafter referred to as GFRP).

  The inner tub 2 includes a bottomed cylindrical main body 2a and a cylindrical neck portion 2b formed on the upper portion of the main body 2a with a diameter smaller than that of the main body 2a. The bottom of the main body 2a is It is formed in an arc shape so as to fit the human head.

  On the inner surface of the arc-shaped bottom portion of the inner tub 2, biomedical sensors (SQUID sensor array) 4 are radially provided by being inserted into the main body 2a of the inner tub 2 from the neck portion 2b. The inner tank 2 is filled with, for example, liquid helium as a coolant for cooling the sensor 4 from the neck portion 2b, and a heat insulating material 5 is provided inside the neck portion 2b.

  The outer tub 3 is formed so as to contain the inner tub 2, and a vacuum layer 6 is formed between the inner wall of the outer tub 3 and the outer wall of the inner tub 2. Further, a vacuum suction port 3a communicating with the vacuum layer 6 is formed on the side surface of the outer tub 3, and the bottom of the outer tub 3 is formed so as to surround the arc-shaped bottom of the inner tub 2. A measuring unit 3b is formed.

  On the outer peripheral surface of the neck portion 2b of the inner tub 2, a doughnut-shaped first thermal anchor 7a for high temperature and a second thermal anchor 7b for low temperature are positioned in the vacuum layer 6 in order, It is fixed to. These thermal anchors 7a and 7b are heat reservoirs made of, for example, copper and having high thermal conductivity and high heat capacity.

  One end of each of the thermal shields 8a and 8b that shields radiant heat from the outside, for example, made of copper, for example, is fixed to the thermal anchors 7a and 7b so as to be thermally conductive. Are arranged in the vacuum layer 6 so as to sequentially surround the inner tank 2.

  The other end of the thermal shield 8b is formed in an arc shape suitable for a human head in the vacuum layer 6 near the arc-shaped bottom of the inner tank 2, and the other end of the thermal shield 8a is an arc shape of the inner tank 2. It is formed linearly up to the vicinity of the bottom.

  A description will be given of a thermal shield effect for preventing heat from entering from the outside in the cryostat configured as described above. The liquid helium in the inner tank 2 is gradually evaporated by intrusion heat due to radiation and conduction from the outside, and the evaporated helium rises through the gap between the neck portion 2b and the heat insulating material 5. At that time, the neck portion 2b is cooled, and the gas absorbs heat to perform heat exchange.

  When the neck portion 2b is cooled, the two-stage thermal anchors 7a and 7b fixed to the neck portion 2b are cooled, and the dual-configuration thermal shield 8a having the end portions fixed to the thermal anchors 7a and 7b. 8b are also cooled and absorb the radiant heat entering from the outside of the outer tub 3. The absorption of this radiant heat provides a thermal shield effect that prevents heat from entering the inner tank 2 from the outside.

  The high temperature thermal shield 8a is set to a relatively high temperature, for example, 100 to 180K, and the low temperature thermal shield 8b is set to a low, 20 to 50K. And, in the gap between the inner tank 2, the thermal shields 8a, 8b, and the outer tank 3, a large number of film-like thin films (not shown) called aluminum superposition in which aluminum is deposited are sandwiched so as not to contact each other, By implementing multiple heat shields, heat penetration due to radiation is made extremely low.

  By the way, such a cryostat has an inner tank 2 exposed to an extremely low temperature and a high degree of vacuum must be maintained between the inner wall of the outer tank 3 and the outer wall of the inner tank 2. Both the tank 2 and the outer tank 3 are manufactured by combining cylindrical containers.

The manufacturing process of the cryostat shown in FIG. 4 is, for example, as follows.
1) Inner tank 2
2) Thermal shield 8b
3) Thermal shield 8a
4) Combination with separately manufactured outer tub 3

  However, the cryostat is formed so that the ends of the inner tank 2 and the outer tank 3 to which the sensor 4 is attached are bent with respect to the other end as shown in FIG. 5 according to the measurement purpose of the biomagnetic measuring device. There are also things.

  Patent Document 1 describes a cryostat configured as shown in FIG.

JP 2002-246663 A

  However, in the cryostat having a complicated shape as shown in FIG. 5, it is difficult to configure the outer tub 3 separately produced by combining cylindrical containers as in FIG. 4, and the thermal shields 8a and 8b are incorporated. It is even more difficult.

  The present invention solves such problems, and an object of the present invention is to provide a cryostat having a structure that can be manufactured relatively easily even with a complicated shape.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a cryostat in which at least a part of an outer tank formed so as to contain an inner tank filled with a cryogenic refrigerant is formed of a cylindrical body,
The cylindrical body is characterized in that at least two divided pieces along the axial direction are reconfigured as a cylindrical body.

The invention according to claim 2 is the cryostat according to claim 1,
The cylindrical body is configured to be bent by combining a plurality of cylindrical bodies.

The invention according to claim 3 is the cryostat according to claim 1 or 2,
A reinforcing member is provided on the outer periphery of the reconstructed cylindrical body.

The invention according to claim 4 is the cryostat according to claim 3,
The reinforcing member is formed in a ring shape.

The invention according to claim 5 is the cryostat according to claim 3,
The reinforcing member is a reinforcing plate provided with a hole through which the reconstructed cylindrical body passes.

  According to the present invention, it is possible to perform high-speed processing of range up / down of a measurement range in accordance with a change in measurement value.

It is a conceptual explanatory view of the present invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows an example of the conventional cryostat. It is a block diagram which shows the other example of the conventional cryostat.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual explanatory diagram of the present invention, and shows a cylindrical body C used as the outer tub 3 of the cryostat shown in FIG. 4, for example, (A) is an overall view, and (B) is a cut view. It is.

  The cylindrical body C is composed of GFRP, and is cut in the axial direction along the cutting lines CL1 and CL2 indicated by broken lines in (A) corresponding to the diameter direction of the end face, as shown in (B). It is divided into a piece C1 and a right piece C2.

A manufacturing process for assembling a straight tube type cryostat as shown in FIG. 4 using the cylindrical body C divided into two as described above is as follows.
1) Inner tank 2
2) Thermal shield 8b
3) Thermal shield 8a
4) Reconstructed as an outer tub 3 of a cylindrical body C divided into a left piece C1 and a right piece C2.

  In reconfiguring the cylindrical body C divided into the left piece C1 and the right piece C2 as a cylindrical outer tank 3 containing the inner tank 2, the thermal shield 8b, and the thermal shield 8a, the left piece C1 is cut. The cut surfaces CP21 and CP22 of the right piece C2 facing the surfaces CP11 and CP12 are overlapped and bonded with an adhesive having high affinity with GFRP and excellent airtightness, or bonded with an O-ring between these cut surfaces To do.

  When the thermal shield 8b and the thermal shield 8a are incorporated in the outer periphery of the inner tub 2, when the cylindrical outer tub 3 integrated as in the prior art is used, a predetermined gap is maintained in the entire periphery. Although it was necessary to be aware of the overall outer shape finish and required considerable man-hours for adjustment, by using the cylindrical body C divided into two as the outer tub 3 as in the present invention, each divided piece of the cylindrical body C As a result, the total assembly adjustment man-hours can be reduced.

  FIG. 2 is a block diagram showing another embodiment of the present invention, which is applied to a bent tube type cryostat as shown in FIG. 5, wherein (A) is a front view and (B) is a partial sectional view. Yes, the same reference numerals are given to the parts common to FIG.

  In FIG. 2, the outer tub 3 is configured by combining and integrating three components P1 to P3 divided along two dividing lines indicated by two-dot chain lines L1 and L2. These three parts P1 to P3 are made of GFRP.

  Specifically, the parts P1 and P2 are cylindrical bodies having one end cut obliquely with respect to the axial direction and the other end cut perpendicularly with respect to the axial direction. These parts P1 and P2 are the same as in FIG. Further, the left piece and the right piece divided into two are reconfigured as a cylindrical outer tub 3.

  The part P3 is a helmet part into which the head of a subject (not shown) is inserted, and is integrated as an outer tank 3 by bonding or bonding to the end of the part P2 reconfigured as a cylindrical outer tank 3.

The manufacturing process for assembling the bent tube cryostat shown in FIG. 2 is as follows.
1) Inner tank 2
2) Thermal shield 8b
3) Thermal shield 8a
4) Reconstructing part P1 as part of cylindrical outer tub 3 5) Reconstructing part P2 as a part of cylindrical outer tub 3 by integrating it with the end of part P1 6) Cylindrical part P3 Reconstructed as an outer tub 3 integrated with the end of

  By adopting such a structure, any cryostat having a complicated shape can be assembled with a relatively small number of man-hours.

  FIG. 3 is a block diagram showing another embodiment of the present invention, in which a ring-shaped reinforcing member RM is attached to the outer periphery of a cylindrical body reconfigured by bonding or bonding.

  When the cylindrical body cut in half along the axial direction is reconfigured into a cylindrical body, the tensile strength is reduced, so that a force in the direction of expanding the cross section is applied when evacuated. Therefore, the reinforcing member RM is attached to the outer periphery of the cylindrical body to prevent the cylindrical body from being deformed.

  The reinforcing member RM is not limited to the ring shape, and may be a reinforcing plate provided with a hole through which the reconstructed cylindrical body passes.

  Moreover, although the cryostat used with a magnetoencephalograph was demonstrated in the said Example, it is not restricted to this, This invention is applicable also to various cryostats.

  Moreover, although the example which divides | segments a cylindrical body into 2 was demonstrated in the said Example, depending on a shape, you may make it 3 or more division | segmentation so that an operation | work may be easy.

  As described above, according to the present invention, a cryostat having a structure that can be manufactured relatively easily even with a complicated shape can be realized.

DESCRIPTION OF SYMBOLS 1 Cryostat 2 Inner tank 2a Main part 2b Neck part 3 Outer tank 4 Sensor 6 Vacuum layer 7a, 7b Thermal anchor 8a, 8b Thermal shield C Cylindrical body CL1, CL2 Cutting line C1 Left piece C2 Right piece CP11, CP12, CP21, CP22 Cut surface RM Reinforcement member P1-P3 Parts

Claims (5)

In a cryostat in which at least a part of an outer tank formed so as to contain an inner tank filled with a cryogenic refrigerant is formed of a cylindrical body,
A cryostat in which the cylindrical body is reconfigured as a cylindrical body by dividing at least two pieces along the axial direction.   The cryostat according to claim 1, wherein the cylindrical body is configured to be bent by combining a plurality of cylindrical bodies.   The cryostat according to claim 1 or 2, wherein a reinforcing member is provided on an outer periphery of the reconfigured cylindrical body.   The cryostat according to claim 3, wherein the reinforcing member is formed in a ring shape.   The cryostat according to claim 3, wherein the reinforcing member is a reinforcing plate provided with a hole through which the reconstructed cylindrical body passes.

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